The present invention relates to powered conveyors and particularly to powered gate conveyors which incorporate a gate system providing a passageway when the gate is opened to enable workers to enter and leave their work area via the powered gate.
The invention provides endless or continuous belt conveyors with pivotal gate sections, but which are substantially the same in form factor as conveyors without such sections, thereby removing restrictions on and increasing the flexibility of use and layout of such conveyors. Gate conveyors provided by the invention are implemented with a single endless belt, which need not be under tension, and is driven in the fixed section of the conveyor. Potentially unsafe conveyor operating conditions are avoided by utilizing pivot hinges located within the confines of the loop of the belt and between the edges thereof so that the joint can readily be guarded and dangerous gaps between the sections are not created when the these sections are closed and the conveyor is in operation.
Continuous conveyors arc in common use. They may be purchased in various sizes and disposed in various arrangements to provide pathways. These pathways may enclose areas in which workers are trapped. In addition, joining conveyors to workbenches may be desirable which restricts the form factor of the conveyor system. Conveyor arrangements that provide an efficient flow of work to enable assembly of product in many areas of a factory floor without trapping workers is facilitated by the gated conveyor provided by the invention.
It has been proposed to provide conveyors with sections that are pivotable or laterally movable to enable arrangements of conveyors which achieve the desired flow of the work without trapping workers. Conveyors with laterally movable gate sections are, for example, shown in Davenport, U.S. Pat. No. 5,873,449, issued Feb. 23, 1999 and a pivotable conveyor section which provides a pass through gate is described in Wheeler, U.S. Pat. No. 5,655,647 issued Aug. 12, 1997. It has also been proposed to provide ladders and platforms which allow workers to enter and leave an area trapped by conveyors.
Pivotable power gates conventionally use separate belts for the gate section and the fixed section thereof A motor drives the belt of the fixed section and another mechanism transfers the power from the drive or fixed section to the belt of the gate section. There is typically a gap between the two continuous belts which is called a xe2x80x9cpinch pointxe2x80x9d. Such pinch points are undesirable because of safety considerations. The transfer mechanism is located outside of the width of the belts, and must be shielded and guarded so as to avoid injury to workers. The form factor of the conveyor is altered to provide room for the transfer mechanism and guards. The pivotal mounting of the gate section is included in the transfer mechanism, engendering the need for bearings and housings which increase conveyor cost. The separate belt of the gate section may be much shorter than the belt in the drive section, which increases difficulties with alignment and set-up for tracking and synchronism of the belts of these sections.
Accordingly, it is the principal object of the present invention to provide an improved conveyor system having a pivotal powered gate section.
A more specific object of the invention is to provide an improved conveyor with a powered gate pivoted on a fixed or drive section of the conveyor which utilizes a single continuous, endless or loop belt, encompassing both conveyors, thereby eliminating the need for transfer mechanisms and avoiding changes in the form factor of the gated conveyor from conventional non-gated conveyors.
It is a still more specific object of the present invention to provide an improved powered gate conveyor system with a gate section which moves into abutment with the fixed or drive section when the gate is closed thereby avoiding pinch points.
It is a still further object of the present invention to provide an improved powered gate conveyor where the gate is counterbalanced and inter-locked with the motor drive, so as to facilitate the safe operation of the conveyor.
It will be understood that the invention may be provided in a manner to effectuate one or more, but not necessary, all of the foregoing objects and features of the invention.
Briefly described, a powered gate conveyor embodying the invention has a fixed section and a gate section. The sections have adjacent ends which are pivotally connected to form a joint within the confines of an endless belt which extends around both of the sections. The belt may be disposed in non-tensioned condition, supported on beds within rails which extend along the outsides of the sections. The gate section is pivoted upwardly to an open position where it may be maintained by a counterbalancing mechanism, and when open, provides a passageway across the width of the conveyor via the gate section. In the closed position, the rails move into abutment avoiding a gap or pinch point between the gate and fixed sections. Interlocks may be provided in the joint region of the conveyor for controlling motivation thereof by a drive associated with the fixed section.